Adapter for lamp-sockets.



PATENTED JULY 3, 1906.

I N. MARSHALL.

ADAPTER- POR LAMP SOCKETS.

APPLICATION TILED JAN. 28. 1905.

UNITED STATES PATENT OFFICE.

NORMAN MARSHALL, OF NEWTON, MASSACHUSETTS, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OFNEW YORK.

Specification of Letters Patent.

Patented July 3, 1906..

Application filed January 28, 1905. Serial No. 243,065.

To all whom it may concern: 7

Be it known that I, NORMAN MARSHALL, of Newton, in the county of Middlesex .and

State of Massachusetts, have invented cer-v T-H socketsfor use in connection with.

incandescent lamps of the Edison type.

It has been customary in supplying Edison lamps to use with T-H sockets to furnish an 'adlapter for each lamp,which is applied to the T- socket and is rovided with terminals to coo crate with t e terminals on the base of the Edison lamp. These adapters are provided witha screw-threaded nut formin a terminal for engaging the screw-threa ed central terminal of the T-H socket and have been held in place in the socket merely by the engagement of these screwthreaded parts. In removing an old lamp from a socket the adapter is usually removed'with the lamp, and it is necessary, therefore, to furnish an adapter for each Edison lamp which is to be used with'a T-H socket, and this has been the usual practice.

The present invention relates to means for preventing the removal of the adapter after it has been once applied to a T-H socket, so

that in removing the lamp the adapter cannot be removed, but remains as a permanent part of the T-H socket, thereby ermanently transforming it into a socket a apted to re ceive Edison lamps. The device for preventing the removal of the adapter from the socket is so formed and arranged that it does not interfere with the application of the adapter to the socket, but will prevent the rotation of the adapter in a direction to unscrew the screw-threaded central terminals after the adapter has been once screwed into lace. Y

p For the purpose of. illustration, I have shown in the accompanying drawings a'T-H socket and an adapter embod g my invention in the forms in which prefer to use them.

In the drawings, Figure 1 is an enlarged sectional view showing a T-H socket with an ada ter applied to the socket. Fig. 2 is a fort er enlarged horizontal section through the central terminal of the adapter looking downward on line 2 2, Fig. 1; and Fig. 3 is a similar view showing a modified form of means for preventing the removal of the adapter.

As shown in the drawings, the adapter is provided with the usual metallic screw-shell A for engaging the outer metallic screw-terminal of the lamp-base and is also provided with, a central internally-screw-threaded nut' B, forming the, metallic terminal for engaging the screw-threaded terminal C of the T-H socket C. The screw-threaded terminal B is secured in a disk D, of insulating material, secured within the up er end of the shell A. The upper end of the 516 A is rovided with a flat annular flan e A, which orms the contact against whic the switch-block of the key mechanism of the socket acts in the usual'manner. The adapteris'also provided with theusual insulating-sleeve F, surrounding the metallic screw=shell A.

As shownin Figs. 1 and'2, the means for preventing the removal ofthe adapter fromthe socket after it has been once screwed into (place consists of a device in the form of a pin which normally rojectsinto the bore of the central termina B of the adapter. This pin is located in a recess b, formed ,in the wall of the terminal B, and is inclined in the direction of rotation of the adapter as it is screwed into thesocket. as'shown, and the walls of the recess 6 are correspondingl tapered, so that the inward movement of t e pm is limited by its engagement with the walls of the recess. The pin is forced 'yieldingly forward by a wire spring H, arran ed in an-annular recess b in the tirminal and bearing on the outer end of t e in.

T e pin does not project into the bore of the terminal B sufiiciently to prevent thev The pin is tapered,

vents the removal of the adapter after it has been once screwed into place without interfering with the application of the adapter to n the socket.

The pin 'may be corrugated or roughened or provided with an edge'or edges which will cut into or become embedded in the thread of the terminal C as force is applied. to the adapter tending to turn it in a direction to unscrew it from the socket.

In Fig. 3, I have shown another form of device for preventing theremoval of the adapter after it has been once screwed into place. In this form the pin G is formed bythe bent end of an annular spring-wire H, arranged in a recess 1) of the terminal B. The pin in this case, as in the other, is inclined in the direc-- tion of the rotation of the adapter in applying it tothe socket and norm-ally projects somewhat into the bore of the terminal, but not sufiici'ently to interfere with the screwing of the adapter into the socket. In this case the pin yields as the adapter is screwed into position, but binds. on the screw-thread of the termina-l C as soon as there is any tendency for the adapter to turn in a reverse direction.

Otherforms and arrangement of the device for preventing the removal of the adapter I may be employed without departing from the invention.

Without attempting to describe all such forms, what I claim, and desire to secure by Letters Patent, is

1. adapter for incandescent lampsprovided with a screw-threaded terminal for engaging a complementaryscrew-threaded terminal of a lamp-socket, means for-supporting the an incandescent lamp, a pin incline direction-of rm'gvernent of the adapter" when screwed into the socket, and means for yield 50 ingly forcing the pin into proximity to the screw-threads on the adapter-terminal.

2. An adapter for incandescent lampsprovided with an internally-screw-threaded terminal for engaging a complementary terminal on" an incandescent-lamp socket, means for securing a lamp to the adapter, a pin mounted on the adapter and inclined in the direction of movement of the adapter upon being screwed into the socket, said terminal having an annular groove, and an annular spring held in the groove in the terminal and yieldingly forcing the pin into the bore of the terminal.

3. An adapterprovided with a central internally-screw threaded terminal for engaging the central terminal of a lamp-socket, a metallic screw-shell, a pin inclined in the direction of movement of the adapter when being screwed into the socket, and means for yieldingly forcing the pin into the bore of the adapter-terminal, substantially as described.

4. An adapter provided with a central in ternally-screw-tlneaded terminal for engaging the central terminal of a lamp-socket, a metallic screw-shell, a pin mounted in the ter- Ininal and inclined in the direction of move- Inent of the adapter when being screwed into the socket, and an annular spring held in a groove in the terminal. and yieldingly forcing the in into the hereof the terminal, substantial y asdescribed.

. 5. An adapter provided with a central-internally-screw-threaded terminal for'engag ing the central terminal of a lamp-socket, a metallic screw-shell, an annular spring H embracing the adapter-terminal, a pin G at the end of the vspring extending through the Wall of the terminal inathe' direction of movement of the adapter when being screwed into the socket, substantially as described.

.Intestimonywhereof I have affixed my signature in presence of two witnesses.

. NORMAN MARSHALL. Witnesses:

IRA 'L. Frsn, KATHARINE A 'Dnenn. 

